Electric pencil sharpener

ABSTRACT

An electric pencil sharpener including a pencil holding unit provided with a start switch, a motor circuit to which there are connected an electric motor and rotating sharpening mechanism operated by said motor, detecting means for detecting the sharpened condition of a pencil, switching means actuated by said detecting means whereby, upon completion of the sharpening of the pencil to a desired first degree, a lamp is illuminated, and upon completion of sharpening to a second sharper degree, the switching means is operated to open the circuit of the motor to stop it with the lamp remaining illuminated, thereby indicating the end of the sharpening so as to prevent the pencil from being excessively sharpened. A flywheel is coupled to the rotating sharpening mechanism to prevent immediate ceasing of rotation thereof upon opening of the motor circuit.

July 25, 1972 United States Patent Imanishi et al.

Masakazu lmanishi; Kenzi Kondou; Ituo Suglura,.al1 of Nagoya, JapanGermany...............,.....:........

e G 1,] 66 99 Ill 35 96 2 21. h -l 0o .11. 1 1

[72] Inventors:

Primary Examiner-Andrew R. Juhasz Assistant Examiner-James F. CoanAttorney-Flynn & Frishauf m L m C k u m E m 0. 8 i mm SL.

.k 3 a kw 0a TK a e n .w s s A M 7 [22] Filed: March 2, 1970 [57]ABSTRACT An electric pencil sharpener including a pencil holding unit[21] App]. No.:

[30] Ford!" Application Priority Data provided with a start switch, amotor circuit to which there are connected an electric motor androtating sharpening mechanism operated by said motor, detecting meansfor detecting the sharpened condition of a pencil, switching meansactuated by said detecting means whereby, upon completion of thesharpening of the pencil to a desired first degree, a lamp isilluminated, and upon completion of sharpening to a second sharperdegree, the switching means is operated to open the 4 22 2 M 7.N&7. 8 8R 3 2 4 I y 4 3M7 00 I n.2,; m m u 8 n 2 8 n M 2 m 4 m .4 ll "84 u ""2 uu u m n n u n m a U u P h a n J u m mum l mmu mm& h G m d 3 SLM M Umw.11.1 2 8, 555 [.ll.

nmAmm a m B 58 e.1 .ISDDO ngea mm mm m m n. c mu 'm f 3y 0 8 w e m n avme 0 d h .m c m m F he m n g o o S. n h e u .I .nn m w We Pm m chm Detf et-U00 1 0 8 1 tnmen 9 S i m o u E OC m n e I Onn L C tic O nlm 2 mep m 1 Pudi er O C eecmf. thh O ttim dtdtm .nm e ee V Vh .n m mh cmPflPo555 2 888 Run 444 44 44 1.11.4 ""1 [56] References Cited UNITED STATESPATENTS 3,486,540 12/1969 2,561,438 7/1951 Duchesneau 2,408,767 10/1946Fleming......... 3, l 25,994 3/1964 Ruskin Patented July 25, 1972 4Sheets-Sheet 1' Patented July 25, 1972 3,678,975

4 Sheets-Sheet 2 Patented July 25, 1972 4 Shoots-Sheet 5 Patented July25, 1972 4 Sheets-Sheet 4- The present invention relates to an electricpencil sharpener and more particularly to an improved pencil sharpenerincluding means for indicating the sharpened condition of a pencil.

There have heretofore been proposed various types of electric pencilSharpeners equipped with means for indicating the time at which therehas been sharpened a pencil to a desired condition so as to prevent itfrom being excessively sharpened. With one type, when the operation ofsharpening a pencil is brought to an end, a sliding member involved in arotary sharpening mechanism is made to slide to actuate a switchinterlocked therewith and there is lighted a lamp disposed in front ofsaid pencil sharpening mechanism. Another type carries out said lampindication in two stages according to the extent of sharpening, that is,the case where the core tip of a pencil is sharpened fine and the casewhere said tip is sharpened relatively thick. A third type indicates theposition of the core tip of a pencil to the user by interlocking anindicator with a sliding member. However, the prior art pencilsharpeners indicate by visual means that the core tip of a pencil hasbeen sharpened to a desired size. Accordingly, they have the drawbacksthat the user must always watch for the time of such indication and thatif he forces a pencil into a sharpener with said indication overlookedor unnoticed then there will be sharpened a pencil to an unnecessaryextent. A further disadvantage is that there is a slight intervalbetween the time said indication is given and the time a pencil isactually taken out, thus leading to excessive sharpening and waste.

An object of the present invention is to provide an electric pencilsharpener including means for indicating the completion of the pencilsharpening operation by stopping a motor so as to eliminate theabove-mentioned shortcomings encountered with the prior art.

Another object of the invention is to provide an electric pencilsharpener including an improved switching unit for controlling theindication of a completed sharpening operation, and which provides asmoothly sharpened pencil.

This invention can be more fully understood from the following detaileddescription when taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a longitudinal sectional view of an electric pencil sharpeneraccording to an embodiment of the present invention;

FIG. 2 is a cross sectional view of a rotary sharpening mechanisminvolved in the electric pencil sharpener of FIG. 1;

FIGS. 3 and 4 jointly represent a pencil holding unit; FIG. 3 is asectional view on line 3--3 of FIG. 4 and FIG. 4 is a sectional view online 44 of FIG. 3;

FIG. 5 is a perspective view of the indicator switch assembly involvedin the electric pencil sharpener of FIG. 1;

FIG. 6 is a sectional view of the upper portion of the indicator switchassembly of FIG. 5;

FIG. 7 is a perspective view of the front portion of the electric pencilsharpener of FIG. 1 when uncovered;

FIG. 8 is a sectional view on line 8-8 of the electric pencil sharpenerof FIG. 1;

FIG. 9 is a cross sectional view of the sharpening mechanism of anelectric pencil sharpener having a cutter holder molded from syntheticresin;

FIG. 10 is a schematic circuit diagram of the electric pencil sharpenerof FIG. I; and

FIG. 11 is a cross sectional view of the electric pencil sharpener ofFIG. 1, showing the manner in which a pencil is sharpened.

Referring to FIG. 1 showing an electric pencil sharpener, numeral 11denotes a housing which consists of a base plate 12 and cover 13disposed thereon. Said housing 11 is separated into a sharpening chamber100 and mechanism chamber 101 by a partition plate 14 erected at thesubstantially central part of said base plate 12. In said sharpeningchamber 100 are provided a rotary sharpening mechanism 15 and squaremounting frame 16 surrounding it. In said mechanism chamber 101 isdisposed a motor 17 for driving said rotary sharpening mechanism 15. Infront of said mounting frame 16 is positioned a pencil holding unit 18for clamping a pencil introduced into the sharpener, and behind saidframe 16 is fixed an internal gear 19. Said mounting frame 16 isattached to a support member 20 projecting forward from said partitionplate 14. Said pencil holding unit 18 contains, as later described, astart switch actuated upon insertion of a pencil, and is furtherprovided with cylindrical members 22 and 23 extending forward andbackward respectively from the substantially central part thereof. Thefront cylindrical member 22 has a screw socket formed on its peripheralsurface and screwed to the cover 13 from the outside by a socket member24. The rear cylindrical member 23 supports said rotary sharpeningmechanism 15. Said pencil holding unit 18 has alamp socket 26 formed atthe top to hold a lamp 25. At that part of said cover 13 which isdisposed opposite to said lamp 25 is formed a lamp window 27 made of,for example, transparent glass or synthetic resin. The lighting of saidlamp 25 indicates that the core tip of a pencil has been sharpenedrelatively thick. The rotary sharpening mechanism 15 consists of acutter holder 28 shown in FIG. 2 and a cutter 30rotatably fitted to saidcutter holder 28 by means of a support plate 29. Said cutter holder 28has a cavity formed at the substantially central part, a balance weight32 provided at the front part which is perforated with a threaded bore31 for allowing said support plate 29 to be screwed in place, acylindrical pencil entry portion 33 projecting to the front side and aConical pencil receiving bore 34 coaxially formed in said cylindricalpencil entry portion 33 in a manner to extend up to the aforementionedcavity provided in the cutter holder 28. On the side wall 7 of saidcutter holder 28 is cut out a depression 35 in which there are embeddedtwo pins 36. To these pins 36 is slidably fitted a sliding member 37 inthe coaxial direction of said pencil receiving bore 34 in such a mannerthat the front end of said sliding member 37 contacts the rear end ofsaid bore 34 and the rear end of said member 37 contacts the front endof the latter described operating rod 38. At the rear end of said cutterholder 28 is disposed a rotatable shaft 39, which has an elongated bore40 penetrating its axial center. Into said elongated bore 40 is slidablyinserted said operating rod 38. Said rotatable shaft 39 engages abearing 41 projecting to the rear side of said partition plate 14.Between said cutter holder 28 and partition plate 14 is interposed athrust washer 42.

As shown in FIG. 2, said cutter 30 assumes a cylindrical shape and has aplurality of spiral blades 43 formed on its peripheral surface. To therear end of said cutter 30 is tightly fitted coaxially therewith acutter pinion 44 in engagement with said internal gear 19. Further, saidcutter 30 is perforated with a shaft hole 45 penetrating its axialcenter. Into said shaft hole 45 is inserted a cutter shaft 46, the rearend of which fits into a shaft receiving hole 47 provided at the rearplane of the aforementioned cavity of the cutter holder 28 and the frontend of which is supported by said support plate 29. This support plate29 consists of a substantially elliptical metal plate, and has a hole 48formed at the substantially central part and two support holes 49 and 50disposed in an approximately symmetrical relationship with respect tosaid central hole 48. Said central hole 48 engages said pencil entryportion 33, and said support hole 49 supports one end of said cuttershaft 46 and said support hole 50 serves to fix said support plate 29 tosaid cutter holder 28 by means of a screw assembly 51 with a washer 52interposed therebetween. Between said cutter 30 and support plate 29,and between said cutter pinion 44 and cutter holder 28 are disposedwashers 53 and 54 respectively. To the rear end of said cutter holdershaft 39 is provided a speed reduction gear assembly which includes aspur gear 55 and pinion 56. The pinion 56 is fixed to the shaft of saidmotor 17. To said spur gear 55 is concentrically fitted a cylindricalfly wheel 57 in a manner to project forward. This fly wheel 57 serves toslow down the speed at which said sharpening mechanism 15 is brought torest. Said fly wheel may be fitted to the sharpening mechanism. To afitting stand 59 mounted on said motor 17 is fixed an indicatorswitching unit 58 actuated by said operating rod 38. Between the upperedge of said partition plate 14 and cover 13 is provided an elasticshielding member 60 madeof, for example, polyurethane rubber to preventpencil shavings. from being carried into said mechanism chamber 101. Insaid sharpening chamber 100 right below said sharpening mechanism 15 isplaced a waste case 61 which is free to be inserted into and taken outof theintervening space between said cover 13 and base plate 12.

The mounting frame 16 may assume a U-shape, with the closed end used inreceiving said pencil holding unit 18 and both walls of the open endscrewed to the partition plate 14. In this case, the internal gear 19 isfitted to the support stand (not shown) of said partition plate 14.

Said pencil holding unit 18 consists, as shown in FIGS. 3 and 4, of acover 62 and body 63. To these components are projectingly fitted saidcylindrical members 22 and 23. Said body 63 contains a cylindricalpencil receiving member 64 extending inward coaxially withsaidcylindiical member 23 and is perforated with three arcuate slits 65equally spaced in the circumferential direction. Into each of said threeslits 65 is slidably inserted a pencil holding leg assembly 68consisting of an arcuate member 66 and leg member 67 projecting inwardfrom the inside of said arcuate member 66 insuch a manner that saidarcuate member 66 is disposed around the outer periphery of saidcylindrical pencil receiving member 64. At the end of that side of saidleg member 67 on which there is inserted a pencil is formed an inclinedplane 67a. In said arcuate member 66 is cut out an arcuate groove 69having a common axial center with said cylindrical pencil receivingmember 64. There is stretched a looped coil spring 70 through saidarcuate grooves 69 fonned in the arcuate members 66 of said three pencilholding leg assemblies 68 inserted into said pencil receiving member 64in such a manner that all said grooves 69 are connected to each other bysaid looped coil spring 70. This looped coil spring 70 is prepared byforming a coil spring into an annular shape and has a tendency tocontract itself toward its axial center. Accordingly, said pencilholding leg assemblies 68 are always urged toward the axial center ofsaid pencil receiving member 64. In the body 63 of said pencil holdingmember 18 is provided said start switch 21 in such a manner that itscontact is located right on said pencil holding leg assemblies 68. Saidstart switch 21 is closed when said pencil holding leg assemblies 68 aredisplaced in position in the radial direction of said cylindrical pencilreceiving member 64.

Theaforementioned pencil holding unit 18 supports a pencil insertedthereinto without eccentrically displacing it, because said pencilholding leg assemblies 68 are subjected to a uniform contracting forceacting toward the axial center by looped coil spring 70.

Said pencil holding leg assemblies 68 need not consist of three units,but may be provided in a larger number with equal spacings therebetweenaround the outer peripheral surface of said pencil receiving member 64.

Said indicator switching unit 58 is used to light an indication lamp andstop the motor. This indicator switching unit 58 consists, as shown inFIGS. and 6, of a switch box 71 and actuating assembly 72. Saidactuating assembly 72 consists of an armature lever 74 and a platespring 75 supported by a common pivot 73. One end of said plate spring75 is attached to one side wall of said switch box 71, and the other endto the side wall of said armature lever 74. Accordingly, said armaturelever 74 is always urged to contact the rear end of said operating rod38 by means of said plate spring 75. Said switch box 71 consists of abody 71a and cover 71b. Said body 710 contains a nonnally opened lampswitch 76 and normally closed stop switch juxtaposed with each other andswitching lever 78 for actuating them. Each of these switches 76 and .77has a stationary contact blade and movable contact blade. Said stopswitch 77 has longer contact blades than those of said. lamp switch 76and the movable contact blade. of said stop switch 77 has a protuberance77a formed at the end. Said switching lever 78 is inserted into saidbody 71b in such a manner that one end of said switching lever 78contacts the armature lever 74 and the other end contacts said lampswitch 76. Further there is formed at said other end a protuberance 79which facesthe protuberance 78 of said stop switch 77 at right angles,and contacts the protuberance 77a of said stop switch 77 when saidswitching lever 78 is displaced. Said switching lever 78 and said lampand stop switches 76 and 77 have such an operational interrelationshipthat when the other end of said switching lever 78 contacts said lampswitch 76 there is allowed a prescribed spacing between the protuberance79 of said switching lever 78 and the protuberance 77a of said stopswitch 77 and that when said switching lever 78 is displaced itsprotuberance 79 contacts the protuberance 77a of said stop switch 77 toopen it.

The electric pencil sharpener of the present invention is furtherimproved as described below. Since an electric pencil sharpenergenerally sharpens a pencil with a rapidly rotating cutter, it has thedrawbacks that pencil shavings are scattered on all sides to bedeposited on the upper surface of the mounting frame or waste case andthat when said box is taken out of the sharpener the shocks caused bysaid removal allow shavings remaining in the sharpener to fall on a deskto contaminate its surface. To eliminate the aforementionedshortcomings, therefore, the electric pencil sharpener of the presentinvention has a shavings guide cover assembly 80 fitted to the mountingframe 16 shown in FIGS. 7 and 8. This cover assembly 80 consists of anupper cover member 800 having a semicircular cross section and two sideplates 80b extending downward from the bottom of both side walls of saidcover member 80a, each of said side plates having two holes 80c cut outon each side. Said upper cover member 804 has such a semicircular crosssection as surrounds the revolving locus of the cutter 30 of saidsharpening mechanism 15 and has a width at least equal to the axiallength of said cutter 30. Said side plates 80b extend downward at leastto the upper edge of said waste case 61. On each side of said mountingframe 16 are provided two hooked portions 81 prepared by bending up acut piece of its side wall. Said cover assembly is fitted to saidmounting frame 16 by allowing the holes 80c of said side plates 80b tobe engaged from the outside by said hooked portions 81 of said frame 16.Said cover assembly 80 may be prepared from an integral combination ofsaid upper cover member 80a and side plates 80b or by separatelyfabricating them, and also fitted to the inside of said mounting frame16 instead of to the outside as practiced in the aforementioned case.Further, the fitting of said cover assembly 80 to the mounting frame 16may be carried out by any other means than described above.-Theprovision of said cover assembly 80 enables scattering pencil shavingsreliably to fall into said shavings box 61, thus avoiding the occurrenceof the aforementioned inconvenience.

Furthermore, said electric pencil sharpener should preferably have acutter holder molded from synthetic resin. The cutter holder of theprior art sharpener is made of die-cast aluminum. It will be apparentthat replacement of said die-cast aluminum with synthetic resin moldingwill realize easy fabrication and appreciable reduction of cost.

There will now be described this second embodiment by reference to theappended drawings. The other parts of said sharpener than the cutterholder are the same as those of the preceding sharpener and descriptionthereof is omitted. As shown in FIG. 9, the cutter holder 82 is moldedfrom synthetic resin. When the cutter 20 is fitted to the cutter holder82, the lightness of synthetic resin material results in unbalancebetween the weight of said material and that of the cutter 20 with themost likely occurrence of vibrations when the sharpener is operated. Toprevent such an occurrence, there is embedded a heavy metal balanceweight 83 in said cutter holder 82 in such a manner that one side ofsaid weight 83 is made flush with the front surface of said cutterholder 82. Atthe central part of said balance weight 83 is formed ascrew socket 84 which serves to allow the support plate 29 for rotatablyThere will now be described by reference to FIG. the circuit of anelectric pencil sharpener according to the aforementioned embodiments.The first output terminal 86 of an AC source 85 is connected to thefirst input terminal 87 of a condenser motor 17 and the second outputterminal 88 is connected to the second input terminal 89 of saidcondenser motor 17 through the start switch 21 and stop switch.77connected in series. The indication lamp 25 and lamp switch 76 areconnected in series. One end of said series connected assembly isconnected to said first input terminal and the other end is connected toa line contacting both start switch 21 and stop switch 77.

There will now be described the operation of said electric pencilsharpener. When there is inserted a pencil from the socket member 24into the sharpener, the start switch 21 is closed to supply current tosaid motor 17. Its rotating moment is transmitted to the rotarysharpening mechanism through the pinion 56 and spur gear 55. Theresultant rotation of said cutter holder 82 causes the cutter gear 44engaging the internal gear 19 to be rotated together with the cutter 30fitted thereto while revolving around the periphery of said internalgear 19. When the pencil is further forced into the pencil receivingbore 34, it is gradually sharpened by said revolving and rotating cutter30, and its core tip contacts the sliding member 37 to urge it backwardand allow the operating rod 38 interlocked with said sliding member 37also to slide backward (FIG. 11). The rear end of said operating rod 38forcefully displaces said armature lever 74. When the sliding member 37is brought to point D shown in FIG. 11, the extent of said displacementis transmitted to said switching lever 78 through said operating rod 38and armature lever 74 to close said lamp switch 76. The closing of saidlamp switch 76 leads to the formation of an electric circuit (FIG. 10)for said lamp 21 to light it, thereby indicating that the pencil hasbeen sharpened. Indication at this stage announces that the pencil coreis sharpened relatively thick. Where it is desired to sharpen the coretip to a finer size, it is only required further to push the pencil intothe sharpener. When it is thus urged, said sliding member 37 is furtherdisplaced and the switching lever 78 is also shifted in position withsaid lamp switch 76 closed. When said sliding member 37 is brought topoint E of FIG. 11 the protuberance 79 on said switching lever 78presses the protuberance 77a of said stop switch 77 to open it. The opening of said stop switch 77 opens the circuit of said motor. The stoppingof said motor prevents any further sharpening of a pencil, indicatingthe completion of said sharpening operation. In this case, the rotarysharpening mechanism 15 does not suddenly stop its rotation, but is soslowly brought to rest as to prevent any further forceful sharpening ofthe pencil due to the rotation inertia of said fly wheel 57. During thetime interval required for the complete stopping of said sharpeningmechanism 15, the pencil is actually a little more sharpened withoutallowing the teeth of said cutter to bite into it, so that it issharpened clean, free from any fine splits. When the pencil is drawn outof the sharpener, the operating rod 38 and sliding member 37 are urgedbackward by the plate spring 75 to extinguish the actuating force ofsaid switching lever 78, causing the normally closed stop switch 77 tobe brought back to its original closed position due to its own elasticforce. Said withdrawal of the pencil again puts the motor in operationto actuate said rotary sharpening mechanism 15. This actuation iscontinued until the pencil is fully taken out of the sharpener, thuspermitting its easy removal. Upon completion of the withdrawal of thepencil, said start switch 21 is opened to stop said motor 17.

Generally the cutter of a pencil sharpener is reduced in its cuttingquality in a relatively short time, namely, when it has been used about5,000 times, so that it has to be replaced with a new one once in awhile. The pencil sharpener of the present invention is so arranged asto allow said replacement to be effected easily. Where it is necessaryto replace the cutter 30, it can be removed simply by taking out saidpencil holding unit 18 together with said cover 13 and pulling the screw51 to remove said support member 29 and cutter shaft 46. When a newcutter is to be fitted, the aforementioned step has only to be reversed.

What we claim is:

1. An electric pencil sharpener comprising:

a housing;

a pencil holding unit disposed on the front inside of said housing toreceive and clamp a pencil to be sharpened, said holding unit includinga start switch operated upon insertion of a pencil for supplying powerto said sharpener;

a motor which is energized responsive to operation of said start switch;

a cutter holder for holding a cutter at a prescribed angle ofinclination;

a fly wheel coupled to said cutter holder;

gear means coupled to the rear end of said cutter holder and engagingwith a gear connected to said motor;

an operating rod slideably mounted in said cutter holder; the positionof said operating rod being a function of the degree of sharpness of thepencil;

switching means operatively coupled to the rear end portion of saidoperating rod which is remote from said holding unit;

said switching means including a normally open contact which is closedto cause a lamp to illuminate when the position of said operating rodcorresponds to a first degree of sharpness of the pencil beingsharpened, and a normally closed contact which is opened when theposition of said operating rod corresponds to a second degree ofsharpness which is sharper than said first degree of sharpness, saidmotor being coupled to said switching means to turn said motor off whensaid normally closed contacts are opened.

2. The sharpener according to claim 1 including means for sliding saidoperating rod rearwardly relative to said cutter holder responsive tothe insertion of the pencil in said sharpener, the degree of slidingbeing a function of the depth of insertion of said pencil in saidsharpener.

3. The sharpener according to claim 2 wherein said means for slidingsaid operating rod includes a sliding member in said cutter holder forcontacting the forward end portion of said operating rod and forcontacting the sharpened point of the pencil inserted in said sharpener,said sliding member sliding rearwardly responsive to increasinginsertion of said pencil.

4. The sharpener according to claim 1 wherein said gear means includes aspur gear coupled to the rear of said cutter holder which is engagedwith a pinion gear coupled to said motor.

5. The sharpener according to claim 4 wherein said fly wheel is acylindrical fly wheel coaxially coupled to said spur gear.

6. The sharpener according to claim 1 wherein said pencil holding unithas a bore therein through which a pencil passes, at last three spacedleg member located about the periphery of said bore .with asubstantially equal spacing therebetween, said leg members being movablein a radial direction relative to said bore and each leg member having agroove therein, an annular spring arranged in said grooves for exertinga substantially equal pressure on each leg member to bias it toward theaxial center of said bore, said leg members clamping the pencil insertedin said sharpener.

7. The sharpener according to claim 1 including a shavings guide coverprovided in said housing to cover a planetary revolving locus of saidcutter.

8. The sharpener according to claim 7 wherein said guide cover isapproximately semicircular in shape.

9. The sharpener according to claim 1 wherein said cutter holder is asynthetic resin molding.

10. The sharpener according to claim 9 including a balance weightembedded in said molded synthetic resin cutter holder to eliminatevibrations upon operation hereof.

11. The sharpener according to claim 1 wherein said lamp remainsilluminated when said normally closed contacts are caused to open and isextinguished upon removal of said pencil from said sharpener wherebysaid starting switch is rendered inoperative.

12. The sharpener according to claim 1 wherein said switching meansincludes a switching lever operably displaca- 3 23 C UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 678, 975 Dated July25 1972 Inventods) Masakazu 'IMANISI-II, et a1 It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

i In the priority claim, Application No."4 4/2044" 1 should becorrectedto 44/20443.

Signed and sealed this 9th day of January 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. 7 ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. An electric pencil sharpener comprising: a housing; a pencil holdingunit disposed on the front inside of said housing to receive and clamp apencil to be sharpened, said holding unit including a start switchoperated upon insertion of a pencil for supplying power to saidsharpener; a motor which is energized responsive to operation of saidstart switch; a cutter holder for holding a cutter at a prescribed angleof inclination; a fly wheel coupled to said cutter holder; gear meanscoupled to the rear end of saId cutter holder and engaging with a gearconnected to said motor; an operating rod slideably mounted in saidcutter holder; the position of said operating rod being a function ofthe degree of sharpness of the pencil; switching means operativelycoupled to the rear end portion of said operating rod which is remotefrom said holding unit; said switching means including a normally opencontact which is closed to cause a lamp to illuminate when the positionof said operating rod corresponds to a first degree of sharpness of thepencil being sharpened, and a normally closed contact which is openedwhen the position of said operating rod corresponds to a second degreeof sharpness which is sharper than said first degree of sharpness, saidmotor being coupled to said switching means to turn said motor off whensaid normally closed contacts are opened.
 2. The sharpener according toclaim 1 including means for sliding said operating rod rearwardlyrelative to said cutter holder responsive to the insertion of the pencilin said sharpener, the degree of sliding being a function of the depthof insertion of said pencil in said sharpener.
 3. The sharpeneraccording to claim 2 wherein said means for sliding said operating rodincludes a sliding member in said cutter holder for contacting theforward end portion of said operating rod and for contacting thesharpened point of the pencil inserted in said sharpener, said slidingmember sliding rearwardly responsive to increasing insertion of saidpencil.
 4. The sharpener according to claim 1 wherein said gear meansincludes a spur gear coupled to the rear of said cutter holder which isengaged with a pinion gear coupled to said motor.
 5. The sharpeneraccording to claim 4 wherein said fly wheel is a cylindrical fly wheelcoaxially coupled to said spur gear.
 6. The sharpener according to claim1 wherein said pencil holding unit has a bore therein through which apencil passes, at last three spaced leg member located about theperiphery of said bore with a substantially equal spacing therebetween,said leg members being movable in a radial direction relative to saidbore and each leg member having a groove therein, an annular springarranged in said grooves for exerting a substantially equal pressure oneach leg member to bias it toward the axial center of said bore, saidleg members clamping the pencil inserted in said sharpener.
 7. Thesharpener according to claim 1 including a shavings guide cover providedin said housing to cover a planetary revolving locus of said cutter. 8.The sharpener according to claim 7 wherein said guide cover isapproximately semicircular in shape.
 9. The sharpener according to claim1 wherein said cutter holder is a synthetic resin molding.
 10. Thesharpener according to claim 9 including a balance weight embedded insaid molded synthetic resin cutter holder to eliminate vibrations uponoperation hereof.
 11. The sharpener according to claim 1 wherein saidlamp remains illuminated when said normally closed contacts are causedto open and is extinguished upon removal of said pencil from saidsharpener whereby said starting switch is rendered inoperative.
 12. Thesharpener according to claim 1 wherein said switching means includes aswitching lever operably displacable by said operating rod for closingsaid normally open contacts, said lever having a protuberance which,upon further displacement of said switching lever, opens said normallyclosed contacts, and biasing means for biasing said switching lever awayfrom said switch contacts.